Herbicidal 2-substituted phenyl-4,5,6,7-tetrahydro-2H-indazoles

ABSTRACT

A 2-substituted phenyl-4,5,6,7-tetrahydro-2H-indazole compound of the formula: ##STR1## wherein X is a chlorine atom or a bromine atom, Y is an oxygen atom or an imino group, Z is a chlorine atom or a methyl group and R is a C 2  -C 4  alkyl group, a C 3  -C 4  alkenyl group or a C 3  -C 4  alkynyl group, which is useful as a herbicide.

This is a continuation-in-part application of our copending applicationSer. No. 536,528, filed Sept. 28, 1983, now abandoned.

The present invention relates to 2-substitutedphenyl-4,5,6,7-tetrahydro-2H-indazoles (hereinafter referred to as"indazole(s)"), and their production and use.

The said indazoles are representable by the formula: ##STR2## wherein Xis a chlorine atom or a bromine atom, Y is an oxygen atom or an iminogroup, Z is a chlorine atom or a methyl group and R is a C₂ -C₄ alkylgroup, a C₃ -C₄ alkenyl group or a C₃ -C₄ alkynyl group.

Between an oxygen atom and an imino group for Y, an oxygen atom isfavorable. In case of Y being an oxygen atom, preferred are theindazoles of the formula (I) wherein Y is an oxygen atom, X is achlorine atom or a bromine atom, Z is a chlorine atom and R is anisopropyl group, an allyl group, a propargyl group or a1-methyl-2-propynyl group. In case of Y being an imino group, preferredare the indazoles of the formula (I) wherein Z is a methyl group and Ris a propargyl group. Specifically preferred are3-chloro-2-(4-chloro-2-fluoro-5-isopropoxyphenyl)-4,5,6,7-tetrahydro-2H-indazole,3-chloro-2-[4-chloro-2-fluoro-5-(1-propynyloxy)-phenyl]-4,5,6,7-tetrahydro-2H-indazole,3-methyl-2-(4-chloro-2-fluoro-5-propargyloxyphenyl)-4,5,6,7-tetrahydro-2H-indazole,etc.

It is known that certain kinds of indazoles are effective as herbicides.For instance, the herbicidal use of3-chloro-2-(4-chloro-2-fluorophenyl)-4,5,6,7-tetrahydro-2H-indazole,3-chloro-2-(2,4-dichloro-5-methoxyphenyl)-4,5,6,7-tetrahydro-2H-indazole,3-methyl-2-(4-chloro-2-fluorophenyl)-4,5,6,7-tetrahydro-2H-indazole,etc. is disclosed in U.S. Pat. Nos. 4,059,434 and 4,124,374. However,their herbicidal effect is not necessarily satisfactory.

It has now been found that the indazoles (I) show a strong herbicidalactivity against a wide variety of weeds including broad-leaved weedsand Graminaceous weeds in agricultural plowed fields as well as weeds inpaddy fields at small doses and do not produce any materialphytotoxicity on various agricultural crops (i.e. corn, wheat, soybean,cotton, rice plant). Examples of broad-leaved weeds are wild buckwheat(Polygonum convolvulus), pale smartweed (Polygonum lapathifolium),common purslane (Portulaca oleracea), common lambsquarters (Chenopodiumalbum), redroot pigweed (Amaranthus retrflexus), radish (Raphanussativus), wild mustard (Brassica kaber), hemp sesbania (Sesbaniaexaltata), velvetleaf (Abutilon theophrasti), prickly sida (Sidaspinosa), cleavers (Galium aparine), ivyleaf morningglory (Ipomoeahederacea), tall morningglory (Ipomoea purpurea), field bindweed(Convolvulus arvensis), jimsonweed (Datura stramonium), black nightshade(Solanum nigrum), birdseye speedwell (Veronica persica), cocklebur(Xanthium strumarium), etc. Examples of Graminaceous weeds against whichthe indazoles (I) show a herbicidal activity are Japanese millet(Echinochloa frumentacea), barnyardgrass (Echinochloa crus-galli), greenfoxtail (Setaria viridis), large crabgrass (Digitaria sanguinalis),annual bluegrass (Poa annua), blackgrass (Alopecurus myosuroides), oat(Avena sativa), wild oat (Avena fatua), Johnsongrass (Sorghumhalepense), quackgrass (Agropyron repens), etc. Typical examples of theweeds which grow in paddy fields are barnyardgrass (Echinochloaoryzicola), monochoria (Monochoria vaginalis), arrowhead (Sagittariapygmaea), false pimpernel (Lindernia pyxidaria), indian toothcup rotala(Rotala indica), bulrush (Scirpus juncoides), slender spikerush(Eleocharis acicularis), long steemed waterwort (Elatine triandra), etc.The indazoles (I) exert an extremely high herbicidal activity againstpaddy field weeds without any phytotoxicity to rice plants. Accordingly,the indazoles (I) can be used as herbicides applicable to agriculturalplowed fields as well as paddy fields. They are also useful asherbicides to be employed for orchard, pasture land, lawn, forest,nonagricultural field, etc. applications.

The indazole (I) is obtainable by reacting a 2,4-dihalo-5-substitutedphenyl-4,5,6,7-tetrahydro-2H-indazole of the formula: ##STR3## wherein Xand Z are each as defined above and A is an amino group or a hydroxylgroup with a halogenated compound of the formula:

    R--B                                                       (III)

wherein R is as defined above and B is a halogen atom.

The reaction is usually carried out in a solvent in the presence orabsence of a base at a temperature of from 0° to 150° C. for a period of0.5 to 20 hours. The halogenated compound (III) is normally employed inan amount of 1 to 3 equivalents with respect to the starting compound(II). The amount of the base may be ordinarily from 1 to 2 equivalentswith respect to the starting compound (II). Examples of the solvent arearomatic hydrocarbons (e.g. benzene, toluene, xylene,), halogenatedhydrocarbons (e.g. chloroform, carbon tetrachloride, dichloroethane,chlorobenzene, dichlorobenzene), ethers (e.g. diethyl ether, diisopropylether, dioxane, tetrahydrofuran, ethylene glycol dimethyl ether), acidamides (e.g. dimethylformamide, dimethylacetamide), water, or theirmixtures. As the base, there may be exemplified organic bases (e.g.pyridine, triethylamine, N,N-diethylaniline), inorganic bases (e.g.sodium hydride, sodium hydroxide, potassium hydroxide, sodium carbonate,potassium carbonate), etc.

The thus produced indazole (I) may be subjected to ordinarypost-treatment and, when desired, purified by a per se conventionalprocedure such as column chromatography or recrystallization.

The indazole (I) wherein Y is an oxygen atom and Z is a chlorine atom isalso obtainable by reacting a substituted phenylhydrazine of theformula: ##STR4## wherein X and R are each as defined above with a2-alkoxycarbonylcyclohexanone of the formula: ##STR5## wherein R' is aC₁ -C₄ alkyl group to give a 2-substituted phenylhexahydroindazol-3-oneof the formula: ##STR6## wherein X and R are each as defined above,followed by reacting the latter with a chlorinating agent.

The first reaction may be carried out in a solvent at a temperature of80° to 200° C. for a period of 0.5 to 20 hours. The2-alkoxycarbonylcyclohexanone (V) is usually employed in an amount of 1to 1.2 equivalents with respect to the substituted phenylhydrazine (IV).Examples of the solvent are toluene, xylene, acetic acid, etc.

The second reaction is normally carried out in a solvent at atemperature of 80° to 200° C. for a period of 5 to 20 hours. Thechlorinating agent may be employed in an excessive amount with respectto the intermediary product (VI). Examples of the chlorinating agent arephosphorus oxychloride, thionyl chloride, phosgene, oxalic dichloride,trichloromethyl chloroformate, etc. Examples of the solvent are toluene,xylene, chloroform, etc.

Further, the indazole (I) wherein Y is an oxygen atom and Z is a methylgroup can be produced by reacting the substituted phenylhydrazine (IV)with 2-acetylcyclohexanone.

The reaction may be carried out in a solvent in the presence of an acidcatalyst at a temperature of 80° to 200° C. for a period of 0.5 to 20hours. The 2-acetylcyclohexanone is usually employed in an amount of 1to 1.2 equivalents with respect to the substituted phenylhydrazine (IV).As the solvent, there may be employed preferably aromatic hydrocarbonssuch as toluene, xylene, α-methylnaphthalene, or a mixture thereof.Examples of the acid catalyst are inorganic acids (e.g. hydrochloricacid, sulfuric acid), organic acids (e.g. acetic acid, p-toluenesulfonicacid), etc.

The thus produced indazole (I) may be subjected to ordinarypost-treatment and, when desired, purified by a per se conventionalprocedure such as column chromatography or recrystallization.

Practical and presently preferred embodiments of the production of theobjective indazoles (I) are illustratively shown below:

EXAMPLE 1

Into a solution of3-chloro-2-(4-chloro-2-fluoro-5-hydroxyphenyl)-4,5,6,7-tetrahydro-2H-indazole(0.9 g) in dimethylformamide (10 ml), there was added potassiumcarbonate (0.25 g) and ethyl iodide (1 g), and the mixture was stirredfor 60° C. for 3 hours. After cooling, water was added to the reactionmixture, followed by extraction with ether. The ether layer was washedwith water twice, dried and concentrated. The residue was crystallizedfrom hexane to give 0.2 g of3-chloro-2-(4-chloro-2-fluoro-5-ethoxyphenyl-4,5,6,7-tetrahydro-2H-indazole(Compound No. 1). m.p., 85.1° C.

EXAMPLE 2

A mixture of2-(4-chloro-2-fluoro-5-isopropoxyphenyl)-1,2,4,5,6,7-hexahydro-3H-indazol-3-one(1 g) and phosphorus oxychloride (0.7 g) was heated under reflux heatingfor 6 hours. After cooling, the reaction mixture was dissolved inchloroform, washed with a 5% sodium hydroxide solution and water, driedand concentrated. The residue was purified by silica gel columnchromatography to give 0.3 g of3-chloro-2-(4-chloro-2-fluoro-5-isopropoxyphenyl)-4,5,6,7-tetrahydro-2H-indazole(Compound No. 2). n_(D) ²⁶ 1.5530.

EXAMPLE 3

4-Chloro-2-fluoro-5-isopropoxyphenylhydrazine (1.8 g),2-acetylcyclohexanone (1.0 g) and a catalytic amount of acetic acid weredissolved in xylene (5 ml). The resultant mixture was heated underreflux for 8 hours while removing water. After cooling, the reactionmixture was concentrated under reduced pressure, and the residue waspurified by silica gel column chromatography to give 0.9 g of3-methyl-2-(4-chloro-2-fluoro-5-isopropoxyphenyl)-4,5,6,7-tetrahydro-2H-indazole(Compound No. 5). n_(D) ¹⁴.5 1.5607.

Examples of the indazole (I) produced in the same manner as above areshown in Table 1.

                  TABLE 1                                                         ______________________________________                                         ##STR7##                      (I)                                            Com-                                                                          pound                              Physical                                   No.   XY       Z      R            property                                   ______________________________________                                        1     ClO      Cl     CH.sub.2 CH.sub.3                                                                          m.p. 85.1° C.                       2     ClO      Cl     CH.sub.2 (CH.sub.3).sub.2                                                                  n.sub.D.sup.26 1.5530                      3     ClO      Cl     (CH.sub.2).sub.3 CH.sub.3                                                                  n.sub.D.sup.28 1.5492                      4     ClO      CH.sub.3                                                                             CH.sub.2 CH.sub.3                                                                          m.p. 98-99° C.                      5     ClO      CH.sub.3                                                                             CH.sub.2 (CH.sub.3).sub.2                                                                  N.sub.D.sup.14.5 1.5607                    6     ClO      Cl     CH.sub.2 CHCH.sub.2                                                                        m.p. 91.3° C.                       7     ClO      Cl                                                                                    ##STR8##    n.sub.D.sup.25 1.5670                      8     ClO      Cl     CH.sub.2 CHCHCH.sub.3                                                                      m.p. 77-78° C.                      9     ClO      Cl                                                                                    ##STR9##    m.p. 52-53.5 ° C.                   10    ClO      Cl     CH.sub.2 CCH m.p.                                                                          116-117° C.                         11    ClO      Cl                                                                                    ##STR10##   n.sub.D.sup.20.7 1.5535                    12    ClO      CH.sub.3                                                                             CH.sub.2 CHCH.sub.2                                                                        m.p. 128° C.                        13    ClO      CH.sub.3                                                                             CH.sub.2 CCH m.p.                                                                          143-144° C.                         14    Cl NH    CH.sub.3                                                                             CH.sub.2 CCH m.p. 117.7° C.                      15    BrO      Cl     CH(CH.sub.3).sub.2                                                                         n.sub.D.sup.22 1.5734                      16    BrO      Cl     CH.sub.2 CHCH.sub.2                                                                        m.p. 101.9° C.                      17    BrO      Cl     CH.sub.2 CCH m.p. 121.2° C.                      18    BrO      CH.sub.3                                                                             CH(CH.sub.3).sub.2                                                                         n.sub.D.sup.19.5 57.32                     ______________________________________                                    

The starting 2,4-dihalo-5-substitutedphenyl-4,5,6,7-tetrahydro-2H-indazole (II) wherein A is a hydroxyl groupand Z is a chlorine atom is obtainable by reacting a2,4-dihalo-5-hydroxyphenylhydrazine of the formula: ##STR11## wherein Xis as defined above with the 2-alkoxycarbonylcyclohexanone (V) in thesame manner as in the reaction between the compound (IV) and thecompound (V) to give a2-(2,4-dihalo-5-hydroxyphenyl)hexahydroindazol-3-one of the formula:##STR12## wherein X is as defined above, followed by reacting the latterwith a chlorinating agent in the same manner as in the reaction betweenthe compound (VI) and the chlorinating agent.

The 2,4-dihalo-5-substituted phenyl-4,5,6,7-tetrahydro-2H-indazole (II)wherein A is a hydroxyl group and Z is a methyl group may be alsoproduced by reacting the 2,4-dihalo-5-hydroxyphenylhydrazine (VII) with2-acetylcyclohexanone in the same manner as in the reaction between thecompound (IV) and 2-acetylcyclohexanone.

The 2,4-dihalo-5-substituted phenyl-4,5,6,7-tetrahydro-2H-indazole (II)wherein A is an amino group is obtainable by reacting a2,4-dihalo-5-nitrophenylhydrazine of the formula: ##STR13## wherein X isas defined above with the 2-alkoxycarbonylcyclohexanone (V) as in thereaction between the compound (IV) and the compound (V) to give a2-(2,4-dihalo-5-nitrophenyl)hexahydroindazole-3-one of the formula:##STR14## wherein X is as defined above, followed by reacting the latterwith a chlorinating agent as in the reaction between the compound (VI)and the chlorinating agent, or by reacting the2,4-dihalo-5-nitrophenylhydrazine (IX) with 2-acetylcyclohexanone as inthe reaction between the compound (IV) and 2-acetylcyclohexanone to givea 2,4-dihalo-5-nitrophenyl-4,5,6,7-tetrahydro-2H-indazole of theformula: ##STR15## wherein X and Z are as defined above, followed bysubjecting the latter to reduction by a per se conventional proceduresuch as reduction with an acid (e.g. hydrochloric acid, acetic acid) andiron powder.

The intermediary phenylhydrazine compounds, i.e. the substitutedphenylhydrazine (IV), the 2,4-dihalo-5-hydroxyphenylhydrazine (VII) andthe 2,4-dihalo-5-nitrophenylhydrazine (IX), may be produced according tothe following scheme: ##STR16## wherein X and R are each as definedabove.

The above conversions are known and described, for instance, in U.S.Pat. Nos. 4,124,374, EP-0061741A, EP-0083055A and J. Chem. Soc.,Commun., 2106 (1970).

Typical examples for the production of the starting compounds areillustratively shown below:

EXAMPLE 4

Production of the 2,4-dihalo-5-substitutedphenyl-4,5,6,7-tetrahydro-2H-indazole (II: X═Z═Cl; A═OH):

A solution of 2-fluoro-4-chloro-5-hydroxyphenylhydrazine (8 g) and2-ethoxycarbonylcyclohexanone (8 g) in acetic acid (30 ml) was heatedunder reflux for 4 hours. After cooling, the precipitated crystals werecollected by filtration and washed with ether to give 11 g of2-(4-chloro-2-fluoro-5-hydroxyphenyl)-2,3a,4,5,6,7-hexahydroindazol-3-one.m.p., 273°-275° C. (decomp.).

The product thus obtained was added to a 1M solution of phosgene intoluene (400 ml), and the resultant mixture was heated under reflux for3 hours. After cooling, the mixture was concentrated, and the residuewas purified by silica gel column chromatography to obtain 3 g of3-chloro-2-(4-chloro-2-fluoro-5-hydroxyphenyl)-4,5,6,7-tetrahydro-2H-indazole.m.p., 183°-185° C.

EXAMPLE 5

Production of the 2,4-dihalo-5-substitutedphenyl-4,5,6,7-tetrahydro-2H-indazole (II: X═Br; Z═Cl; A═OH):

In the same manner as in Example 4 but using4-bromo-2-fluoro-5-hydroxyphenylhydrazine, there was obtained3-chloro-2-(4-bromo-2-fluoro-5-hydroxyphenyl)-4,5,6,7-tetrahydro-2H-indazole.m.p., 174.3° C.

EXAMPLE 6

Production of the 2,4-dihalo-5-substitutedphenyl-4,5,6,7-tetrahydro-2H-indazole (II: X═Cl; Z═CH₃ ; A═OH):

4-Chloro-2-fluoro-5-hydroxyphenylhydrazine (0.5 g),2-acetylcyclohexanone (0.4 g) and a catalytic amount of acetic acid wereadmixed with xylene (15 ml), and the resultant mixture was heated underreflux for 5 hours while removing water. After cooling, the mixture wasconcentrated, and the residue was purified by silica gel columnchromatography to obtain 0.7 g of2-(4-chloro-2-fluoro-5-hydroxyphenyl)-3-methyl-4,5,6,7-tetrahydro-2H-indazole.m.p., 188.5°-190° C.

EXAMPLE 7

Production of the 2,4-dihalo-5-substitutedphenyl-4,5,6,7-tetrahydro-2H-indazole (II: X═Cl; Z═CH₃ ; A═NH₂):

A mixture of iron powder (3 g) and a 5% aqueous acetic acid solution (10ml) was heated to 90° to 100° C. while stirring for 10 minutes. To theresulting mixture, there was dropwise added2-(4-chloro-2-fluoro-5-nitrophenyl)-3-methyl-4,5,6,7-tetrahydro-2H-indazole(2 g) in acetic acid (10 ml) and ethyl acetate (10 ml), followed bystirring at the same temperature for 1 hour. After cooling, the ironpowder was eliminated by filtration, and the filtrate was extracted withethyl acetate. The organic layer was washed with a saturated sodiumbicarbonate solution, dried and concentrated. The crystallized residuewas collected by filtration and washed with ether to obtain 1.8 g of2-(4-chloro-2-fluoro-5-aminophenyl)-3-methyl-4,5,6,7-tetrahydro-2H-indazole.m.p., 107°-108° C.

Some examples of the 2,4-dihalo-5-substitutedphenyl-4,5,6,7-tetrahydro-2-H-indazole (II) wherein A is an amino groupproduced in the same manner as in Example 7 are shown in Table 2.

                  TABLE 2                                                         ______________________________________                                         ##STR17##                    (II)                                            X    Z             Physical property                                          ______________________________________                                        Br   Cl            Glassy                                                     Br   CH.sub.3      m.p. 69-71° C.                                      ______________________________________                                    

EXAMPLE 8

Production of the substituted phenylhydrazine (VII):

4-Chloro-2-fluoro-5-hydroxyaniline (10 g) was dissolved in conc.hydrochloric acid (130 ml) under heating, and the resultant mixture wascooled to 0° C. To the resulting mixture, there was dropwise added asolution of sodium nitrite (4.5 g) in water (20 ml). After completion ofthe addition, the mixture was further stirred at 5 to -5° C. for 1 hour,and urea was added thereto, whereby excessive sodium nitrite ion wasdecomposed. The resulting mixture was cooled to -30° to -25° C., and asolution of anhydrous stannous chloride (20.5 g) in conc. hydrochloricacid (40 ml) was added thereto, followed by stirring at -10° to 0° C.for 3 hours. The precipitated crystals were collected by filtration,washed with a small amount of water and dissolved in a 10% aqueoussodium hydroxide solution. The resultant solution was adjusted to pH 7and extracted with ethyl acetate. The extract was dried andconcentrated. The crystallized residue was washed with ether to obtain 1g of 4-chloro-2-fluoro-5-hydroxyphenylhydrazine. m.p., 149°-150° C.(decomp.).

Some examples of the substituted phenylhydrazines (IX) and (IV) producedin the same manner as in Example 8 are shown in Tables 3A and 3B.

                  TABLE 3A                                                        ______________________________________                                         ##STR18##                    (IX)                                                   X   Physical property                                                  ______________________________________                                               Cl  m.p. 116-117° C.                                                   Br  m.p. 110-111° C.                                            ______________________________________                                    

                  TABLE 3B                                                        ______________________________________                                         ##STR19##                    (IV)                                            X         R           Physical property                                       ______________________________________                                        Cl        CH(CH.sub.3).sub.2                                                                        m.p. 67-68° C.                                   Cl        CH.sub.2 CCH                                                                              m.p. 67-67.5° C.                                 Br        CH(CH.sub.3).sub.2                                                                        m.p. 65-65.5° C.                                 ______________________________________                                    

EXAMPLE 9

Production of the2,4-dihalo-5-nitrophenyl-4,5,6,7-tetrahydro-2H-indazole (XI):

In the same manner as in Example 6 but using4-chloro-2-fluoro-5-nitrophenylhydrazine (4 g), 2-acetylcyclohexanone(2.8 g), a catalytic amount of acetic acid and xylene (10 ml), there wasproduced 2.3 g of2-(4-chloro-2-fluoro-5-nitrophenyl)-3-methyl-4,5,6,7-tetrahydro-2H-indazole.m.p., 143°-144° C.

EXAMPLE 10

Production of the2,4-dihalo-5-nitrophenyl-4,5,6,7-tetrahydro-2H-indazole (XI):

In the same manner as in Example 5 but using a solution of4-chloro-2-fluoro-5-nitrophenylhydrazine (4.6 g),2-ethoxycarbonylcyclohexanone (3.9 g) in acetic acid (20 ml), there wasprepared2-(4-chloro-2-fluoro-5-nitrophenyl)-2,3a,4,5,6,7-hexahydroindazol-3-one(4.2 g).

The thus obtained product was treated with a 1M solution of phosgene intoluene (300 ml) in the same manner as in Example 5 to obtain 0.8 g of3-chloro-2-(4-chloro-2-fluoro-5-nitrophenyl)-4,5,6,7-tetrahydro-2H-indazole.m.p., 120°-122° C.

EXAMPLE 11

Production of the nitroaniline (XIII):

4-Chloro-2-fluoroaniline (23 g) was dissolved in conc. sulfuric acid(120 ml), and the resultant mixture was cooled to -20° C., followed bydropwise addition of fuming nitric acid (15 g). The reaction mixture wasstirred at -20° to -15° C. for 1.5 hours, poured into ice-water and thenextracted with ether. The ether extract was washed with water and asaturated sodium bicarbonate solution, dried and concentrated. Theresidue was crystallized from a mixture of toluene and hexane (2:1) toobtain 20 g of 4-chloro-2-fluoro-5-nitroaniline. m.p., 83°-84.5° C.

EXAMPLE 12

In the same manner as in Example 11 but using 4-bromo-2-fluoroaniline,there was obtained 4-bromo-2-fluoro-5-nitroaniline. m.p., 90°-92° C.

In the practical usage of the indazoles (I), they may be applied in anypreparation form such as emulsifiable concentrates, wettable powders,suspensions, granules, etc. in combination with a conventional solid orliquid carrier or diluent, a surface active agent or an auxiliary agent.

The content of the indazole (I) as the active ingredient in suchpreparation form is usually within a range of 0.03 to 80% by weight,preferably of 0.07 to 70% by weight.

Examples of the solid carrier or diluent are kaolin clay, attapulgiteclay, bentonite, terra alba, pyrophyllite, talc, diatomaceous earth,calcite, walnut powders, urea, ammonium sulfate, synthetic hydroussilicate, etc. As the liquid carrier or diluent, there may beexemplified aromatic hydrocarbons (e.g. xylene, methylnaphthalene),alcohols (e.g. isopropanol, ethylene glycol, cellosolve), ketones (e.g.acetone, cyclohexanone, isophorone), soybean oil, cotton seed oil,dimethylsulfoxide, acetonitrile, water, etc.

The surface active agent used for emulsification, dispersion ofspreading may be any of the anionic and non-ionic type of agents.Examples of the surface active agent include alkylsulfates,alkylarylsulfonates, dialkylsulfosuccinates, phosphates ofpolyoxyethylenealkylaryl ethers, polyoxyethylene alkyl ethers,polyoxyethylene alkylaryl ethers, polyoxyethylene polyoxypropylene blockcopolymers, sorbitan fatty acid esters, polyoxyethylene sorbitan fattyacid esters, etc. Examples of the auxiliary agents includeligninsulfonates, sodium alginate, polyvinyl alcohol, gum arabic, CMC(carboxymethyl cellulose), PAP (isopropyl acid phosphate), etc.

Practical embodiments of the herbicidal composition according to theinvention are illustratively shown in the following examples whereinparts and % are by weight. The compound number of the active ingredientcorresponds to these shown in Table 1.

PREPARATION EXAMPLE 1

Fifty parts of Compound No. 1, 8 or 13, 3 parts of calciumligninsulfonate, 2 parts of sodium laurylsulfate and 45 parts ofsynthetic hydrous silicate are well mixed while being powdered to obtaina wettable powder.

PREPARATION EXAMPLE 2

Ten parts of Compound No. 2, 3 or 10, 14 parts ofpolyoxyethylenestyrylphenyl ether, 6 parts of calciumdodecylbenzenesulfonate and 70 parts of cyclohexanone are well mixedwhile being powdered to obtain an emulsifiable concentrate.

PREPARATION EXAMPLE 3

Two parts of Compound No. 2 or 10, 1 part of synthetic hydrous silicate,2 parts of calcium ligninsulfonate, 30 parts of bentonite and 65 partsof kaolin clay are well mixed while being powdered. The mixture is thenkneaded with water, granulated and dried to obtain granules.

PREPARATION EXAMPLE 4

Twenty-five parts of Compound No. 1, 2 or 8 is mixed with 3 parts ofpolyoxyethylene sorbitan monooleate, 3 parts of carboxymethyl celluloseand 69 parts of water and pulverized until the particle size of theactive ingredient becomes less than 5 microns to obtain a suspension.

PREPARATION EXAMPLE 5

0.07 Part of Compound No. 10 or 13, 1 part of synthetic hydroussilicate, 4 parts of sodium dodecylbenzenesulfonate, 30 parts ofbentonite and 64.93 parts of kaolin clay are well mixed while beingpowdered. The mixture is then kneaded with water, granulated and driedto obtain granules.

The indazoles (I) thus formulated in any suitable preparation form areuseful for the pre-emergence or post-emergence control of undesiredweeds by soil or foliar treatment as well as flood fallowing treatment.These treatments include the application to the soil surface prior to orafter the transplanting or the incorporation into the soil. The foliartreatment may be effected by spraying the herbicidal compositioncontaining the indazoles (I) over the top of the plants. It may also beapplied directly to the weeds if care is taken to keep the chemical offthe crop foliage.

The indazoles (I) of the invention may be used together with otherherbicides to improve their activity as herbicides, and in some cases, asynergistic effect can be expected. Further, they may be applied incombination with insecticides, acaricides, nematocides, fungicides,plant growth regulators, fertilizers, soil improvers, etc.

The dosage rate of the indazoles (I) may vary on prevailing weatherconditions, preparation used, prevailing season, mode of application,soil involved, crop and weed species, etc. Generally, however, thedosage rate is from 0.01 to 40 grams, preferably from 0.05 to 30 grams,of the active ingredient per are. The herbicidal composition of theinvention prepared in the form of an emulsifiable concentrate, awettable powder or a suspension may ordinarily be employed by dilutingit with water at a volume of 1 to 10 liters per are, if necessary, withaddition of an auxiliary agent such as a spreading agent. Examples ofthe spreading agent include, in addition to the surface active agents asnoted above, polyoxyethylene resin acid (ester), ligninsulfonate,abietylenic acid salt, dinaphthylmethanedisulfonate, paraffin, etc. Thecomposition prepared in the form of granules may be normally applied assuch without dilution.

The biological data of the indazoles (I) as herbicides will beillustratively shown in the following Examples wherein the phytotoxicityto crop plants and the herbicidal activity on weeds were observedvisually as to the degree of germination as well as the growthinhibition and rated with an index 0, 1, 2, 3, 4 or 5, in which thenumeral "0" indicates that no material difference is seen in comparisonwith the untreated plant and the numeral "5" indicates the completeinhibition or death of the test plants.

The compounds shown in Table 4 below were used for comparison.

                  TABLE 4                                                         ______________________________________                                        Com-                                                                          pound                                                                         No.   Chemical structure      Remarks                                         ______________________________________                                               ##STR20##              U.S. Pat. No. 4,059,434                         B                                                                                    ##STR21##              Synthesized for comparison n.sub.D.sup.25.5                                   1.5551                                          C                                                                                    ##STR22##              U.S. Pat. No. 4,059,434                         D                                                                                    ##STR23##              U.S. Pat. No. 4,124,374                         E                                                                                    ##STR24##              U.S. Pat. No. 4,124,374                         F                                                                                    ##STR25##              Commercially available herbicide; "Chlo-                                      methoxynil"                                     G                                                                                    ##STR26##              Commercially available herbicide; "aci-                                       fluorufen"                                      H                                                                                    ##STR27##              Commercially available herbicide; "oxyfluorf                                  en"                                             ______________________________________                                    

TEST EXAMPLE 1 p Vats (33 cm×23 cm×11 cm) were filled with upland fieldsoil and the seeds of corn, wheat, soybean, cotton, oat (Avena sativa),barnyardgrass (Echinochloa crus-galli), large crabgrass, green foxtail,hemp sesbania, cocklebur, velvetleaf, tall morningglory, redroot pigweedand black nightshade were sowed therein. Cultivation was carried out ina greenhouse for 18 days. A designed amount of the test compoundformulated into an emulsifiable concentrate according to PreparationExample 2 and diluted with water containing a spreading agent wassprayed to the foliage of the test plants over the top by means of asmall hand sprayer at a spray volume of 5 liters per are. Thereafter,the test plants were further grown in the greenhouse for 20 days, andthe herbicidal activity and the phytotoxicity were examined. At the timeof the application, the growing stage of the test plants varieddepending on their species but, they were generally at the 1 to 4 leafstage and at a height of 2 to 12 cm. The results are shown in Table 5.

                                      TABLE 5                                     __________________________________________________________________________                         Herbicidal Activity                                      Com-    Phytotoxicity   Barn-                                                                             Large                                                                             Green                                                                             Hemp         Tall      Black              pound                                                                             Dosage     Soy-                                                                             Cot-  yard-                                                                             crab-                                                                             fox-                                                                              ses-                                                                              Cock-                                                                             Velvet-                                                                            morning-                                                                           Redroot                                                                            night-             No. (g/are)                                                                           Corn                                                                             Wheat                                                                             bean                                                                             ton                                                                              Cat                                                                              grass                                                                             grass                                                                             tail                                                                              bania                                                                             lebur                                                                             leaf glory                                                                              pigweed                                                                            shade              __________________________________________________________________________     2  0.32                                                                              1  1   4  3  1  5   4   3   5   5   5    5    5    5                      0.16                                                                              1  0   3  2  0  4   3   2   5   5   5    4    4    4                      0.08                                                                              0  0   2  1  0  3   0   1   5   5   5    3    3    2                   3  0.32                                                                              1  1   3  4  3  5   4   4   5   5   5    5    5    5                      0.16                                                                              0  0   2  2  1  4   3   2   5   5   5    4    4    4                      0.08                                                                              0  0   1  1  0  3   2   1   4   4   5    3    3    3                   5  0.32                                                                              0  0   -- -- -- 4   --  --  5   5   5    5    5    5                      0.16                                                                              0  0   2  -- -- 3   --  --  5   4   5    4    5    5                   9  0.32                                                                              3  1   -- 5  -- 5   --  --  5   5   5    5    5    5                      0.16                                                                              1  0   -- 3  -- 4   --  --  5   5   5    4    5    5                  10  0.32                                                                              3  2   4  5  4  5   5   5   5   5   5    5    5    5                      0.16                                                                              1  1   3  5  3  5   4   5   5   5   5    5    5    5                      0.08                                                                              1  0   2  5  2  4   3   3   5   5   5    5    5    5                  11  0.32                                                                              3  1   -- 5  -- 5   --  --  5   5   5    5    5    5                      0.16                                                                              1  0   -- 4  -- 4   --  --  5   5   5    5    5    5                  13  0.32                                                                              -- 1   -- -- -- 5   --  --  5   5   5    5    5    5                      0.16                                                                              -- 1   -- -- -- 4   --  --  5   5   5    5    5    5                  14  0.32                                                                              3  1   -- -- -- 4   --  --  5   4   5    5    5    5                      0.16                                                                              1  0   -- -- -- 3   --  --  5   4   5    4    5    5                  A   0.32                                                                              1  0   3  3  0  1   0   0   4   3   4    2    1    3                      0.16                                                                              1  0   2  2  0  0   0   0   2   2   3    0    1    2                      0.08                                                                              0  0   1  1  0  0   0   0   1   1   1    0    0    1                  B   0.32                                                                              0  0   2  3  0  0   0   0   3   2   4    1    2    3                      0.16                                                                              0  0   1  1  0  0   0   0   2   0   3    0    0    1                  D   5.0 2  2   3  -- -- --  --  --  4   4   5    5    5    --                     1.25                                                                              1  1   3  -- -- --  --  --  3   3   5    2    5    --                     0.32                                                                              1  1   3  -- -- --  --  --  2   1   3    1    3    --                 C   1.25                                                                              1  1   2  4  2  1   2   2   5   3   3    4    5    4                      0.32                                                                              0  0   1  2  0  0   1   0   3   1   1    2    3    2                  __________________________________________________________________________

TEST EXAMPLE 2

Wagner's pots (1/5000 are) were filled with paddy field soil, and theseeds of barnyardgrass (Echinochloa oryzicola), broad-leaved weeds (e.g.false pimpernel, toothcup, waterwort) and hardstem bulrush and the budsof slender spikerush were sowed therein at a depth of 1 to 2 cm. Waterwas poured therein to make a flooded condition. Rice seedlings of the3-leaf stage were transplanted therein and grown in a greenhouse. Fourdays (at that time barnyardgrass started to germinate) thereafter, adesigned amount of the test compound formulated in an emulsifiableconcentrate according to Preparation Example 2 and diluted with water(10 ml) was applied to the pots by perfusion. The test plants were grownfor an additional 20 days in the greenhouse, and the herbicidal activityand the phytotoxicity were examined. The results are shown in Table 6.

                  TABLE 6                                                         ______________________________________                                                Phyto-                                                                              Herbicidal activity                                             Com-          toxicity        Broad-       Hard                               pound Dosage  Rice    Barnyard-                                                                             leaved                                                                              Slender                                                                              stem                               No.   (g/are) plant   grass   weed  spikerush                                                                            bulrush                            ______________________________________                                        1     0.32    1       5       5     5      5                                        0.16    1       5       5     5      4                                        0.08    0       5       5     4      2                                  2     0.32    1       5       5     5      5                                        0.16    1       5       5     5      4                                        0.08    0       5       5     4      2                                  3     0.32    1       5       5     5      4                                        0.16    1       5       5     4      2                                        0.08    0       4       5     3      1                                  5     0.32    0       5       5     5      4                                        0.16    0       4       5     4      4                                  6     0.32    1       5       5     5      5                                  7     0.32    1       5       5     5      5                                  8     0.32    1       5       5     5      5                                  9     0.32    1       5       5     5      4                                  10    0.16    1       5       5     5      5                                        0.08    1       5       5     5      4                                        0.04    0       5       5     4      3                                  11    0.32    1       5       5     5      5                                        0.16    1       5       5     5      5                                  13    0.32    1       5       5     5      4                                        0.16    1       5       5     5      4                                  14    0.32    1       5       5     5      4                                        0.16    1       5       5     4      4                                  A     0.32    1       4       5     4      4                                        0.16    1       3       5     3      4                                        0.08    0       2       5     2      2                                  B     0.32    1       3       5     3      3                                        0.16    1       2       5     1      2                                        0.08    0       1       5     0      0                                  C     0.32    2       3       5     3      2                                        0.16    0       1       4     2      0                                        0.08    0       0       2     0      0                                  F     1.25    1       4       5     5      4                                        0.32    0       2       5     2      2                                  ______________________________________                                    

TEST EXAMPLE 3

Cylindrical plastic pots (diameter, 10 cm; length, 10 cm) were filledwith upland field soil, and the seeds of barnyardgrass, velvetleaf, tallmorningglory and redroot pigweed were sowed therein. A designed amountof the test compound formulated into an emulsifiable concentrate anddiluted with water was sprayed to the soil surface over the top by meansof a small hand sprayer at a spray volume of 10 liters per are and thesoil was admixed well to the depth of 4 cm. Cultivation was carried outin a greenhouse for 20 days, and the herbicidal activity and thephytotoxicity were examined. The results are shown in Table 7.

                  TABLE 7                                                         ______________________________________                                        Com-          Herbicidal activity                                             pound Dosage  Barnyard- Velvet-                                                                              Tall     Redroot                               No.   (g/are) grass     leaf   morningglory                                                                           pigweed                               ______________________________________                                         1    40      5         5      5        5                                           20      5         5      5        5                                           10      4         5      4        5                                      2    40      5         5      5        5                                           20      5         5      5        5                                           10      5         5      4        5                                      3    40      5         5      5        5                                           20      5         5      4        5                                           10      4         5      3        5                                      4    20      5         5      5        5                                           10      5         5      3        5                                      5    20      5         5      5        5                                           10      5         5      3        5                                      6    20      5         5      5        5                                           10      5         5      4        5                                      7    20      5         5      5        5                                           10      5         5      4        5                                      8    20      5         5      5        5                                           10      5         5      4        5                                      9    20      5         5      5        5                                           10      5         5      4        5                                     10    20      5         5      5        5                                           10      5         5      5        5                                            5      5         5      4        5                                     11    40      5         5      5        5                                           20      5         5      5        5                                     12    20      5         5      5        5                                           10      5         5      3        5                                     13    20      5         5      5        5                                           10      5         5      4        5                                     14    20      4         5      5        5                                           10      4         5      3        5                                     15    40      5         5      5        5                                           20      5         5      5        5                                     16    40      5         5      5        5                                           20      5         5      5        5                                     17    40      5         5      5        5                                           20      5         5      5        5                                     A     40      5         5      3        5                                           20      5         5      2        5                                           10      5         3      1        5                                     B     40      5         4      3        5                                           20      4         3      2        4                                     C     40      4         4      2        4                                           20      2         3      2        4                                     E     40      3         4      1        4                                           20      1         1      1        3                                     ______________________________________                                    

TEST EXAMPLE 4

Vats (33 cm×23 cm×11 cm) were filled with upland field soil, and theseeds of soybean, cocklebur, tall morningglory, velvetleaf, blacknightshade, jimsonweed, green foxtail and barnyardgrass (Echinochloacrus-galli) were sowed therein at the depth of 1 to 2 cm. A designedamount of the test compound formulated into an emulsifiable concentrateaccording to Preparation Example 2 and diluted with water was sprayed tothe soil surface over the top by means of a small hand sprayer at aspray volume of 10 liters per are. Thereafter, cultivation was carriedout in the outdoors for 20 days, and the herbicidal activity and thephytotoxicity were examined. The results are shown in Table 8.

                                      TABLE 8                                     __________________________________________________________________________              Phyto-                                                                             Herbicidal activity                                            Compound                                                                            Dosage                                                                            toxicity   Tall         Black        Green                                                                             Barnyard-                  No.   (g/are)                                                                           Soybean                                                                            Cocklebur                                                                           morningglory                                                                         Velvetleaf                                                                          nightshade                                                                          Jimsonweed                                                                           foxtail                                                                           grass                      __________________________________________________________________________     1    2.5 1    5     5      5     5     5      5   5                                 1.25                                                                             0    4     5      5     5     5      5   5                           2    2.5 1    5     5      5     5     5      5   5                                 1.25                                                                             0    4     5      5     5     5      5   5                           5    5   0    --    5      5     5     --     5   5                                2.5 0    --    4      5     5     --     4   3                           9    5   1    5     5      5     5     5      5   5                                2.5 0    4     4      5     5     5      5   5                          10    2.5 1    5     5      5     5     5      5   5                                 1.25                                                                             1    5     5      5     5     5      5   5                          11    5   1    5     5      5     5     5      5   5                                2.5 0    4     5      5     5     5      5   5                          13    5   --   5     5      5     5     --     5   5                                2.5 1    --    4      5     5     --     5   4                          G     2.5 3    3     4      4     5     5      3   3                                 1.25                                                                             0    1     1      3     4     4      1   0                          __________________________________________________________________________

TEST EXAMPLE 5

Concrete pots (50×50 cm) were filled with paddy field soil, and theseeds of barnyardgrass, broad-leaved weeds (e.g. common falsepimpernel,indian toothcup, water-wort) and monochoria and the statoblasts ofneedle spikerush were sowed at a depth of 1 to 2 cm. Water was pouredtherein to make a flooded condition. Rice seedlings of the 3-leaf stagewere transplanted therein and grown in the outdoors. Four daysthereafter, a designed amount of the test compound formulated ingranules according to Preparation Example 5 was applied to the pots withtwo replications. The test plants were grown for an additional 40 daysin the outdoors, and the growth inhibition percentage was determined byweighing the fresh weight of the test plants and calculated according tothe following equation: ##EQU1##

The results are shown in Table 9.

                  TABLE 9                                                         ______________________________________                                                  Growth inhibition percentage (%)                                                            Barn- Broad-                                          Compound                                                                              Dosage  Rice    yard- leaved                                                                              Mono- Needle                              No.     (g/are) plant   grass weed  choria                                                                              spikerush                           ______________________________________                                         2      0.28    0       100   100   100   100                                         0.14    0       100   100   100    85                                 10      0.12    0       100   100   100   100                                         0.06    0       100   100   100    90                                 F       4       0        80   100    90    80                                         2       0        40    60    60    30                                 ______________________________________                                    

What is claimed is:
 1. A 2-substitutedphenyl-4,5,6,7-tetrahydro-2H-indazole compound of the formula: ##STR28##wherein X is a chlorine atom or a bromine atom, Y is an oxygen atom oran imino group, Z is a chlorine atom or a methyl group and R is a C₂ -C₄alkyl group, a C₃ -C₄ alkenyl group or a C₃ -C₄ alkynyl group.
 2. Thecompound according to claim 1, wherein Y is an oxygen atom.
 3. Thecompound according to claim 1, wherein X is a chlorine atom or a bromineatom, Y is an oxygen atom, Z is a chlorine atom and R is an isopropylgroup, an allyl group, a propargyl group or a 1-methyl-2-propynyl group.4. The compound according to claim 1, wherein X is a chlorine atom or abromine atom, Y is an imino group, Z is a methyl group and R is apropargyl group.
 5. The compound according to claim 1, which is3-chloro-2-(4-chloro-2-fluoro-5-isopropoxyphenyl)-4,5,6,7-tetrahydro-2H-indazole.6. The compound3-chloro-2-[4-chloro-2-fluoro-5-(1-propynyloxy)phenyl]-4,5,6,7-tetrahydro-2H-indazole.7. The compound3-methyl-2-(4-chloro-2-fluoro-5-propargyloxy)phenyl-4,5,6,7-tetrahydro-2H-indazole.8. A herbicidal composition which comprises as an active ingredient aherbicidally effective amount of the compound according to claim 1, andan inert carrier or diluent.
 9. A method for controlling weeds whichcomprises applying a herbicidally effective amount of the compoundaccording to claim 1 to the area where weeds grow or will grow.
 10. Themethod according to claim 9, wherein the area is an area where riceplants grow or will grow.